Study On The Seepage Layer Hydraulic Gradient Of Slope Under Stable Seepage

In the seepage through earth dam or In-situ leaching,there is an area called boundary effect whose hydraulic gradient has a non-linear relation,and the area is defined as the seepage layer.The seepage failure begins from the infiltration of export,and the export is the infiltration of fluid infiltration portal.The seepage control measures to ensure the ultimate goal of seeping layer suffer from seepage computation of hydraulic gradient variation of seepage is exudation layer,which is also an important factor of retrogressive landslide.However,now in the research of slope stability on the superficial layer of this part is not much,damage parts of permeability of rock and soil,and on the rock soil seepage failure area,types and evolution are also lack of corresponding theory,which cause to the design specifications such as in situ ion type rare earth ore leaching in the lack of clear rules.So it just relies on the experience of the excavation of diversion hole or recovery roadway of liquor and a direct impact on the mine.In view of this,this paper systematically discusses the variation law of hydraulic gradient and seepage failure characteristics of the ion type rare earth ore deposit:(1)Extensively seeking and reading the ion type rare earth ore mining technology,in-situ leaching rule of seepage and slope seepage failure mode and mechanism analysis method of slope stability,slope related monographs and literature of science and technology,sum up and summarize.(2)Through the indoor seepage test of horizontal column leaching,study on the relationship between the average hydraulic gradient and the exudation of layer thickness.The experimental results show that the nonlinear change of hydraulic gradient occurs leakage layer,when the average hydraulic gradient is 0.13,exudation of thickness of 70 cm,with the average hydraulic gradient increases,exudation layer thickness increases,when the average hydraulic the gradient is 0.40,exudation layer thickness is 120cm;vertical velocity increases in the samples with a cross section of the specimen;although there are initial hydraulic gradient,but the initial hydraulic gradient hydraulic gradient effect on exudation layer is small,the velocity and hydraulic gradient layer can be used from the linear fitting,the laminar flow of water appears in exudation layer.(3)Based on theoretical analysis and one-dimensional infiltration test,indoor model test of ion type rare earths,observe the piezometric tube,the seepage of slope angle and the effect of upstream water level and other factors on the slope seepage law.The experimental results show that with the increasing of infiltration head,exudation layer thickness increases.Theinfiltration head height from 70 cm to 90 cm,when the slope angle is 45 degrees,exudation layer thickness increases from 93 cm to 153cm;when the slope angle is 60 degrees,exudation layer thickness increases from 130 cm to 175 cm.The greater slope angle,exudation layer thickness is greater.The hydraulic gradient of different horizontal exudation layer different,in the same cross section at the horizontal position with increasing hydraulic gradient decreases.From infiltration end to end leakage seepage velocity increasing,superficial layer of memory in the same cross section at the vertical velocity component is more and more big phenomenon,and from the end of infiltration.The closer phenomenon is,the more obvious is that the seepage of non seepage layer is Darcy flow,and the seepage of the seepage layer is non Darcy flow.